Open AccessImpact of land‐use change to J atropha bioenergy plantations on biomass and soil carbon stocks: a field study in M ali
Author(s) -
Degerickx Jeroen,
Almeida Joana,
Moonen Pieter C.J.,
Vervoort Leen,
Muys Bart,
Achten Wouter M.J.
Publication year - 2016
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12288
Subject(s) - jatropha , bioenergy , environmental science , biomass (ecology) , carbon sequestration , greenhouse gas , soil carbon , land use, land use change and forestry , agroforestry , biofuel , agronomy , climate change mitigation , land use , forestry , biodiesel , soil water , ecology , soil science , geography , biology , carbon dioxide , biochemistry , catalysis
Small‐scale Jatropha cultivation and biodiesel production have the potential of contributing to local development, energy security, and greenhouse gas ( GHG ) mitigation. In recent years however, the GHG mitigation potential of biofuel crops is heavily disputed due to the occurrence of a carbon debt, caused by CO 2 emissions from biomass and soil after land‐use change ( LUC ). Most published carbon footprint studies of Jatropha report modeled results based on a very limited database. In particular, little empirical data exist on the effects of Jatropha on biomass and soil C stocks. In this study, we used field data to quantify these C pools in three land uses in Mali, that is, Jatropha plantations, annual cropland, and fallow land, to estimate both the Jatropha C debt and its C sequestration potential. Four‐year‐old Jatropha plantations hold on average 2.3 Mg C ha −1 in their above‐ and belowground woody biomass, which is considerably lower compared to results from other regions. This can be explained by the adverse growing conditions and poor local management. No significant soil organic carbon ( SOC ) sequestration could be demonstrated after 4 years of cultivation. While the conversion of cropland to Jatropha does not entail significant C losses, the replacement of fallow land results in an average C debt of 34.7 Mg C ha −1 , mainly caused by biomass removal (73%). Retaining native savannah woodland trees on the field during LUC and improved crop management focusing on SOC conservation can play an important role in reducing Jatropha's C debt. Although planting Jatropha on degraded, carbon‐poor cropland results in a limited C debt, the low biomass production, and seed yield attained on these lands reduce Jatropha's potential to sequester C and replace fossil fuels. Therefore, future research should mainly focus on increasing Jatropha's crop productivity in these degraded lands.